What effect does temperature change have on amalgam?

The correct answer highlights how temperature fluctuations can lead to percolation of fluids within an amalgam restoration. This phenomenon, known as thermal expansion, occurs because dental amalgam expands when heated and contracts when cooled. As the temperature changes, the differences in expansion and contraction between the amalgam and the surrounding tooth structure can create microscopic gaps. These gaps can allow for the movement of fluids—such as saliva or dental pulp fluids—between the restoration and the tooth, which may lead to discomfort, sensitivity, or even decay due to bacteria penetrating into the tooth structure.

Understanding this effect is crucial for dental professionals, as it emphasizes the importance of effective sealing and proper techniques during the placement of amalgam restorations. Although discoloration, softening, or changes in stability may occur with amalgam under specific and less common circumstances, the primary concern of fluid percolation due to temperature changes is a well-documented and significant effect that dental professionals need to consider when evaluating the performance and longevity of dental amalgams.